Listening with headphones is almost an exercise in personal bondage. You're movement is limited by the length of the headphone cable. Stylish, lightweight, and comfortable Sennheiser RS140 wireless RF headphone system features a switchable dynamic compression system for excellent speech intelligibility and a balance control for optimum right/left volume adjustment. If necessary, a high output level can be adjusted to compensate for moderate hearing loss. Enjoy wireless freedom of sound with exceptional sound adaptation. Using Radio Frequencies for its wireless technology, you're free to travel around your home while listening to your sounds without disturbing others. At the core, it's all about the enjoyment of listening without restriction. For that, the RS140 is essential. Optimum signal reception due to self-learning automatic level control Extremely comfortable to wear, ightweight Range - up to 150 meters (RS 140 - 864 MHz) or up to 100 m (RS 140 - 926 MHz) Easy recharging - simply hang the headphones onto the charging cradle / Rechargeable NiMH batteries included Optional wall mounting (transmitter) possible Acoustic signals provide feedback on many functions Operating time per full charge - Up to 23 hours Sennheiser USA 2-year warranty